Wire screening



Nov. 9, 1965 W. A. HOFMANN WIRE SCREENING Original Filed Aug. 19, 1959INVENTOR. WALTER A. H P AN Qwwmq ORNE Y5 United States Patent 3,216,677WIRE SCREENING Walter A. Hofmann, Lyndhurst, Ohio, assignor to TheWarner 81 Swasey Company, Cleveland, Ohio, a corporation of OhioOriginal application Aug. 19, 1959, Ser. No. 834,784, now Patent No.3,076,252. Divided and this application July 20, 1962, Ser. No. 211,215

1 Claim. (Cl. 24S10) The present invention relates to screening and inparticular to wire screening having a selvage edge.

This application is a divisional application of my allowed copendingapplication, Serial No. 834,784, filed August 19, 1959, now Patent No.3,076,252.

The principal object of the present invention is the provision of a newand improved screening free of wire ends projecting beyond the edgesthereof so that the screening may be readily and easily manually handledby a person grasp-ing the edge thereof without danger of cuttinghimself.

A further object of the present invention is the provision of a new andimproved wire screening having a finished selvage edge which is lessbulky than selvage edges produced by prior art methods, and wherein theselvage is quite flexible and does not detract from the flexibility oruses for the screening.

A further object of the present invention is the provision of a new andimproved wire screening having a finished selvage edge which isinexpensive to manufacture and wherein the screening will not ravel andmay be readily, efficiently and safely handled and used in any desiredmanner.

A more specific object of the present invention is the provision of anew and improved wire screening having warp wires and Weft wires withthe opposite ends of the weft wires projecting beyond the oppositeoutermost warp wires and wherein the projecting ends of the weft wiresare substantially embedded in plastic strip which bonds the ends of theweft wires together, fills the space between the ends of the weft wires,and eliminates projecting ends of the weft wires which may tend to cut aperson handling the screening.

A further object of the present invention is the provision of a new andimproved screening, as noted in the next preceding paragraph wherein,the plastic strip has one edge which is flush with the projecting endsof the weft wires and the other edge of the plastic strip is spacedoutwardly from the adjacent outermost warp wire so as not to impair theflexibility of the screening.

Further objects and advantages of the present invention will be apparentto those skilled in the art to which it relates from the followingdetailed description thereof, made with reference to the accompanyingdrawings forming a part of the specification, and in which:

FIG. 1 is a plan view of a length of wire screening embodying thepresent invention;

FIG. 2 is a diagrammatic view of an apparatus for forming the screeningshown in FIG. 1;

FIG. 3 is a plan view of wire screening manufactured by the apparatusshown in FIG. 2 during the various stages of manufacture; and

FIG. 4 is an enlarged sectional view of the screening shown in FIG. 3taken approximately along section line 44 of FIG. 3.

The preferred embodiment of the present invention is shown by way ofexample as embodied in a length of wire screening A shown in FIG. 1. Thelength of wire screening A includes warp threads or wires 10, weftthreads or Wires 11, and opposite finished selvage edges. The left andright selvage edges, as viewed in FIG. 1, comprise ICC strips of fusiblematerial 12, 13, respectively, in which the opposite end portions 14 ofthe weft wires which project beyond the opposite outermost warp wires 15are embedded. The opposite outer edges 16 and 17 of the strips 12, 13,respectively, are flush with the outer ends of the weft wires and theinner edges 18, 19 of the strips 12, 13, respectively, are spacedoutwardly from the adjacent outermost warp wire 15.

The strips of fusible material 12 and 13 bond together the various endportions 14 of the weft wires projecting beyond the left and rightoutermost warp wires 15 and provide smooth, nonbulky edges on thescreening to facilitate handling and prevent raveling of the screening.Moreover, the fusible strips are extremely flexible and do not detractfrom the flexibility of the screening nor limit the uses thereof.

The strips of fusible material 12, 13, which form the finished selvageedges, are preferably a thermoplastic, synthetic fiber such as nylonmade from caprolactam with a 10% monomer plasticizer. Other suitablefusible materials may also be used, for example, polyethylene,polypropylene, polyester and vinyl.

The screening illustrated may be made by a relatively simplemanufacturing process. The selvage edges are formed in the illustratedpreferred embodiment by weaving fusible warp threads or strands into thescreening at the oposite edges and then melting or fusing the strands toform the plastic strips 12, 13 in which the projecting ends 14 of theweft wires are embedded. Preferably, a plurality of fusible strands arewoven into the screening adjacent each edge. As shown in FIG. 3, a pairof warp wires 10a provide the outboard Warp threads along each edge ofthe screening during the manufacture thereof, and immediately inward ofthe warp wires 10a along each edge of the screening are, in theillustrated embodiment, a pair of thermoplastic warp strands 10b. Itwill be understood that the number of fusible warp strands may bevaried. The warps 10a may be termed binding wires since they functionprimarily to keep the thermoplastic strands 10b in place. Thethermoplastic strands 10b are preferably of a larger diameter than thewarp wires 10 to provide the necessary material for embedding andbonding the projecting ends 14 of the weft wires together.

The warp Wires 10a and 101) are woven with the weft wires byconventional weaving apparatus, not shown, and then pass to a suitableheating station 25, at which the warp strands 10b are heated to renderthem plastic and fiowable. The heating station 25, as shown, cornprisesa pair of spaced heating elements 26 adjacent each edge of the screeningbetween which the edges of the screen pass. The heating elements 26 maybe electrical or heated in any other suitable manner to providesufiicient temperature to permit the fusing of the adjacentthermoplastic warps 10b into one plastic mass which bonds itself to theprojecting ends 14 of the weft wires and fills the spaces therebetween.The heating should be uniform and preferably renders the fusiblematerial plastic and fiowable to fuse the strands 10b and bond thematerial to the projecting end portions 14 of the weft wires.

From the heating station 25, the screening passes to a rolling station30 where each selvage edge passes between a pair of rollers 31 whichapply pressure to the heated plastic masses formed from the strands toeven or smooth out the plastic strips 12, 13 and to assure the fusingtogether of the adjacent thermoplastic strands 10b and the bonding ofthe thermoplastic strip formed thereby to the projecting end portions 14of the weft wires to provide the finished plastic selvage edges. Themelted warp strands 10b flow into the spaces between the weft wires tofairly till the spaces and encase the ends 14 of the weft wires,

as shown in FIG. 3. The weft wires will be substantially embedded in theplastic mass and bonded together by strips 12, 13.

After the plastic strips 12, 13 are rolled to form a smooth and evenselvage edge the screening is delivered to a slitting station 40 where acircular knife 41 adjacent each edge of the screening slits the outboard'side of the fused and set material to remove the outboard warp wires aand the outboard portions 42 of the weft wires so that the remaining endportions 14 do not extend beyond the plastic strips 12, 13. Thisprovides a straight, relatively nonragged, plastic selvage edge, wherethe opposite outer edges 16, 17 of the plastic strips 12, 13, re-'spectively, are flush with the outer ends of the weft wires and theinnermost edges 18, 19 of the plastic strips 12, 13, respectively, arespaced outwardly from the adjacent outermost warp wire 15.

The screening, following the removal of the outboard warp wires 10a andthe provision of the smooth, even plastic strips 12, 13 on the oppositeedges, is dried and painted in any conventional manner. The fusiblematerial used to form thefinished selvage edges is preferably selectedto have a sufiiciently high melting temperature so that the screeningcan be painted and dried in conventional drying temperatures, usuallyabout 350 F. without adversely affecting the plastic strips 12, 13. Whennylon is used to form the plastic strips the melting point can be variedby varying the percentage of plasticizer therein, as will be readilyappreciated by those skilled in the art, to achieve the desired meltingtemperatures. Melting temperatures of 400 to 450 F. are suitable formost commercial processes.

The preferred embodiment of the present invention has been described inconsiderable detail and it is to be understood that other modifications,constructions and arrangements are contemplated and it is my intentionto hereby cover all constructions, modifications and arrangements of thepresent invention that fall within the ability of those skilled in theart to which it relates and the scope and spirit of the appended claim.

Having thus described by invention, I claim:

Wire screening including a plurality of spaced warp wires and aplurality of spaced weft wires, said weft wires having end portionsprojecting beyond the opposite outermost warp wires, a substantiallysmooth surfaced strip of fusible thermoplastic material of substantiallyuniform thickness bonded to the end portions of the weft wiresprojecting beyond each outermost warp wire, each of said stripssubstantially filling the space between adjacent weft wires andencircling the end portions of the weft wires projecting beyond eachoutermost warp Wire and in embedding relation therewith, and each ofsaid strips lying outwardly of the adjacent outermost warp wire and theoutermost edge thereof being flush with the outer ends of the weft wiresto which it is bonded and the other edge thereof being spaced outwardlyfrom the adjacent outermost warp wire.

References Cited by the Examiner UNITED STATES PATENTS 2,211,081 8/40Sinclair 245-10 2,659,958 11/53 Johnson 139425.5 2,718,791 9/55 Hose etal. 2,840,117 6/58 Scruggs 28-73 FOREIGN PATENTS 199,574 9/58 Austria.

CHARLES W. LANHAM, Primary Examiner. WHITMORE A. WILTZ, Examiner.

